Exercise can hurt healthy people

Thursday

May 31, 2012 at 6:00 AMMay 31, 2012 at 8:37 AM

By Gina Kolata THE NEW YORK TIMES

Could exercise actually be bad for some healthy people? A well-known group of researchers, including one who helped write the scientific paper justifying national guidelines that promote exercise for all, say the answer may be a qualified yes.

By analyzing data from six rigorous exercise studies involving 1,687 people, the group found that about 10 percent actually got worse on at least one of the measures related to heart disease: blood pressure and levels of insulin, HDL cholesterol or triglycerides. About 7 percent got worse on at least two measures. And the researchers say they do not know why.

“It is bizarre,” said Claude Bouchard, lead author of the paper, published Wednesday in PLoS One, and a professor of genetics and nutrition at the Pennington Biomedical Research Center, part of the Louisiana State University system.

Dr. Michael Lauer, director of the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute, the lead federal research institute on heart disease and strokes, was among the experts not involved in the provocative study who applauded it. “It is an interesting and well done study,” he said.

Others worried about its consequences.

“There are a lot of people out there looking for any excuse not to exercise,” said William Haskell, emeritus professor of medicine at the Stanford Prevention Research Center. “This might be an excuse for them to say, `Oh, I must be one of those 10 percent.’ ”

“That should make folks happy,” said Dr. William E. Kraus, a co-author of the study who is a professor of medicine and director of clinical research at Duke. He was a member of the committee providing the scientific overview for the Department of Health and Human Services’ national exercise guidelines, which advise moderate exercise for at least 150 minutes a week.

Authors of the study say people should continue to exercise as before, but, might also consider getting their heart disease risk factors checked on a regular basis. No intervention, including drugs, works for everyone, Kraus said. So it should not be surprising that exercise does not work for some.

“I am an exercise guy — I believe in exercise for health,” Kraus said. “I would rather have everyone exercise. But you can’t ignore the data.”

Still, he added, there are other reasons to exercise — for mental health and to improve physical functioning.